GLIBC 2.16 支持systemtap静态检查点

* New configure option –enable-systemtap builds SystemTap static probes
into libc for setjmp and longjmp and into libpthread for various operations.
So far the setjmp/longjmp probes and some of the libpthread probes are
provided only for i*86 and x86_64.
Implemented by Roland McGrath and Rayson Ho.

lll_lock_wait – probe in low-level (assembly language) locking code, only fired
when futex/FUTEX_WAIT is called (i.e. when trying to acquire a
contented lock)
arg1 = pointer to futex
arg2 = flags passed to the futex system call
lll_lock_wait_private – probe in low-level (assembly language) locking code,
only fired when futex/FUTEX_WAIT is called (i.e. when
trying to acquire a contented lock)
arg1 = pointer to futex